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At the heart of modern oxide chemistry lies the recognition that beneficial (as well as deleterious) materials properties can be obtained by deliberate deviations of oxygen atom occupancy from the ideal stoichiometry. Conversely, the capability to control and confine oxygen vacancies will be important to realize the full potential of perovskite ferroelectric materials, varistors and field-effect devices. In transition metal oxides, oxygen vacancies are generally electron donors, and in strontium titanate (SrTiO3) thin films, oxygen vacancies (unlike impurity dopants) are particularly important because they tend to retain high carrier mobilities, even at high carrier densities. Here we report the successful fabrication, using a pulsed laser deposition technique, of SrTiO3 superlattice films with oxygen doping profiles that exhibit subnanometre abruptness. We profile the vacancy concentrations on an atomic scale using annular-dark-field electron microscopy and core-level spectroscopy, and demonstrate absolute detection sensitivities of one to four oxygen vacancies. Our findings open a pathway to the microscopic study of individual vacancies and their clustering, not only in oxides, but in crystalline materials more generally. [ABSTRACT FROM AUTHOR]

Micropatterning of single crystals for technological applications is a complex, multistep process. Nature provides alternative fabrication strategies, when crystals with exquisite micro-ornamentation directly develop within preorganized frameworks. We report a bio-inspired approach to growing large micropatterned single crystals. Micropatterned templates organically modified to induce the formation of metastable amorphous calcium carbonate were imprinted with calcite nucleation sites. The template-directed deposition and crystallization of the amorphous phase resulted in the fabrication of millimetersized single calcite crystals with sub-10-μm patterns and controlled crystallographic orientation. We suggest that in addition to regulating the shape, micropatterned frameworks act as sites for stress and impurity release during the amorphous-to-crystalline transition. The proposed mechanisms may have direct biological relevance and broad implications in materials synthesis. [ABSTRACT FROM AUTHOR]

Presents a study that described the multifunctional processing board of the fast track trigger (FTT) of the electron-proton collider Hadron-Electron-Ring-Aniage. Background on the FTT; Features of the FTT multifunctional processing board; Discussion on the application-specific software of the multifunctional processing board.

Demonstrates that by increasing the doping level of polymer layers in organic light-emitting diodes (OLEDs), the barrier to hole injection can be continuously reduced. Findings which suggest that it is possible to significantly reduce the operating voltage of such devices while improving the light output and efficiency; Explanation of the three kinds of hole-injecting anodes employed in the devices; Use of electrochemistry for screening purposes.

Reviews the plays `Phedre' and `Britannicus,' by Jean Racine and performed by the Almeida Theatre Company on January 9, 1999.

Purpose: To critically review the current recommendations regarding the eligibility of patients with myocardial infarction for thrombolytic therapy.Data Identification: Relevant studies published from January 1980 to January 1990 were identified through a computerized search of the English-language literature using MEDLINE and by a manual search of the bibliographies of all identified articles.Study Selection: All randomized, controlled trials of intravenous thrombolysis in acute myocardial infarction and unstable angina were reviewed. Smaller, observational studies and previous review articles were included when relevant to the discussion.Data Extraction: Key data were extracted from each article, including the proportions of patients eligible for thrombolysis, the reasons for exclusion from thrombolytic therapy, and the clinical outcomes of patients treated and of those excluded from treatment. The validity of certain exclusion criteria was examined using subgroup analysis from the large, randomized mortality trials of intravenous thrombolysis and observations from smaller, nonrandomized studies.Results Of Data Synthesis: To date, relatively few patients with myocardial infarction have been considered eligible for fibrinolytic therapy. In this group, both early and late mortality have been significantly reduced. Patients excluded from thrombolysis, however, continue to have a high early mortality. The data suggest that the potential benefits of this treatment might be extended to selected high-risk subgroups. In particular, the risk-benefit ratio may favor the inclusion of otherwise healthy elderly patients; certain patients presenting more than 6 hours after the onset of symptoms; and patients with a history of controlled systolic hypertension or brief, nontraumatic cardiopulmonary resuscitation. The data do not support the use of fibrinolytic therapy as primary treatment in patients with unstable angina or suspected myocardial infarction in the absence of confirmatory electrocardiographic changes.Conclusions: The full potential of thrombolytic therapy to alter the natural history of acute myocardial infarction can only be realized through the continued evaluation of selection criteria and the identification and treatment of the greatest possible number of eligible patients. [ABSTRACT FROM AUTHOR]

The development of microarray patches for vaccine application has the potential to revolutionise vaccine delivery. Microarray patches (MAP) reduce risks of needle stick injury, do not require reconstitution and have the potential to enhance immune responses using a fractional vaccine dose. To date, the majority of research has focused on vaccine delivery with little characterisation of local skin response and recovery. Here we study in detail the immediate local skin response and recovery of the skin post high density MAP application in 12 individuals receiving 3 MAPs randomly assigned to the forearm and upper arm. Responses were characterised by clinical scoring, dermatoscopy, evaporimetry and tissue viability imaging (TiVi). MAP application resulted in punctures in the epidermis, a significant transepidermal water loss (TEWL), the peak TEWL being concomitant with peak erythema responses visualised by TiVi. TEWL and TiVi responses reduced over time, with TEWL returning to baseline by 48 h and erythema fading over the course of a 7 day period. As MAPs for vaccination move into larger clinical studies more variation of individual subject phenotypic or disease propensity will be encountered which will require consideration both in regard to reliability of dose delivery and degree of inherent skin response. [ABSTRACT FROM AUTHOR]

The author reflects on the important issue of reforming premedical education in the U.S. He cites several reasons for enhancing, overhauling, or abolishing the traditional premedical education requirements. He mentions various solutions proposed to enhance premedical education. He also discusses lessons from the Humanities and Medicine Program (HuMed).

For the first time in thirty five years, the clockspeed of the fastest commercial computer chips has not increased. Is the semiconductor industry just pausing for breath or about to suffer a fate similar to that of aerospace? [ABSTRACT FROM AUTHOR]

We present measurements of identified hadron spectra in e+e-→ hadrons from the BABAR and SLD experiments at respective c.m. energies of 10.54 GeV and 91.2 GeV. The scaling violations between the two energies are found to be large and described by hadronization models for charged pions, but not for heavier hadrons. SLD measurements show large differences between b&bmacr;b, c&bmacr;c and light-flavor events that are qualitatively consistent with expectations. The light flavor events are somewhat more consistent with the predictions of MLLA QCD than are events of all flavors, but a discrepancy in the mass dependence remains. SLD have made several new and/or improved measurements of light leading particle production, paving the way for future tagging of u, d and s jets. They have also made a unique study of signed rapidity correlations, showing direct evidence for charge ordering of protons along the quark-antiquark axis. [ABSTRACT FROM AUTHOR]

We have examined the interfaces in Zr-silicate gate dielectrics grown on Si substrates using electron energy loss spectroscopy. The Zr-silicate interface is found to be stable with the Si substrate and the polycrystalline silicon (poly-Si) electrode under annealing to 1050 °C. At this interface, a 0.35 nm wide Zr-free interface region is observed in the as-deposited film, and does not change on annealing. The Zr-free region is too thin to take on the bulk SiO[sub 2] electronic structure, and thus is unlikely to compromise the dielectric properties of the device. For films with an Al electrode, a 2 nm reaction layer forms at the Zr-silicate interface. © 2001 American Institute of Physics. [DOI: 10.1063/1.1426268]. [ABSTRACT FROM AUTHOR]

Reviews the drama 'Le Bourgeois Gentilhomme,' performed by Martine Chevalier and Michel Robin, written by Moliere, directed by Jean-Louis Benoit.

In this letter, we report on electrical and microstructural properties of ultrathin zirconia dielectrics grown on SiO[sub 2] by ultraviolet (UV) ozone oxidation and natural oxidation (no UV light). Capacitance–voltage (C–V) measurements were performed at multiple frequencies on capacitors fabricated from a ZrO[sub 2]–SiO[sub 2] stack. It was found that the C–V curves from samples grown by natural oxidation were distorted and showed severe frequency dependence while samples grown with UV light exposure under otherwise identical conditions had superior electrical behavior. Loss tangent measurements and detailed electron energy loss spectroscopy studies performed on the two samples revealed that the sample grown by natural oxidation was highly oxygen deficient, and this led to its poor electrical properties. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have studied rapidity correlations between pairs of identified π[sup ±], K[sup ±] and p/&pmacr;. Shortrange charge correlations are observed between all combinations of these hadron species, indicating local conservation of quantum numbers and charge ordering in the jet fragmentation process. Long-range correlations are observed in u, d, s-flavor events for all pair types, providing new information on leading particle production. Different correlations observed in c- and b-events are consistent with expectations for B and D hadron decays. The SLC electron beam polarization was used to tag the quark hemisphere in each event, allowing the first study of rapidities signed such that positive rapidity is along the quark rather than antiquark direction. Ordered differences in signed rapidity between pairs of particles provide many new probes of the fragmentation process, including the first direct observation of baryon number ordering along the quark-antiquark axis. [ABSTRACT FROM AUTHOR]

Secondary mitral regurgitation (MR) and heart failure are mutually dependent. Secondary MR occurs as a consequence of heart failure in patients with impaired left ventricular (LV) function, decreasing cardiac efficiency, accelerating a decline in contractility and worsening the already dismal prognosis of these patients. Advances in transcatheter techniques have now given promise to improved survival, outcomes, and quality of life for patients with advanced heart failure and secondary MR. Although transcatheter edge-to-edge repair is well established, transapical transcatheter mitral valve implantation (TMVI) may represent a more durable solution for correction of secondary MR without the need for cardiopulmonary bypass. Correction of MR, however, is thought to acutely increase LV afterload due to the elimination of low afterload regurgitant flow. In high-risk patients, this may cause acute decompensated heart failure. Off-pump TMVI on a beating heart poses a number of unique challenges, but also the opportunity to study invasive haemodynamic indices in high-risk heart failure patients for the first time. In the following discussion, we review the acute haemodynamic changes during off-pump TMVI in patients with heart failure in order to better guide optimal patient selection and management. [ABSTRACT FROM AUTHOR]

Discusses the use of transmission electron energy-loss spectroscopy (EELS) to obtain a map of sp2 and sp3 carbon at a spatial resolution of less than a nanometer across the silicon surface. Diversification of applications of diamond by the discovery of the chemical deposition process for film formation; Nucleation of diamond; Nature of carbon bonding at the interface.

A personal narrative is presented which explores the author's experience of cumulative sleep deprivation when he was a medical intern.

Background: Cardiac resynchronization therapy (CRT) is a well‐established treatment for patients with drug refractory heart failure. Objectives: This study sought to compare the longest RVsense to LVsense activation time (sLAT) versus the longest RVpace to LVsense activation time (pLAT) as the programmed site for left ventricular (LV) pacing in CRT patients with quadripolar LV leads at 3 months. Methods: This single site, double‐blinded, prospective trial, randomized patients 1:1 into the sLAT or pLAT group to determine response. LV pacing was programmed at implant and maintained through 3 months of follow‐up. The 6‐minute hall walk (6MHW) test, NYHA, Minnesota living with heart failure, and clinical composite score (CCS) at the 3 months was compared. Results: N = 92 patients (73M:19F age 66 ± 11.3 years) were randomized implanted and programmed per protocol. Baseline characteristics were comparable. N = 39 sLAT and N = 34 pLAT completed the 3‐month visit for final analysis. Significant improvement from baseline to 3 months was seen in the sLAT group from 253.9 (+/−11.5) to 323.1 (+/−11.9) P =.001. Similarly, the pLAT group improved from 274.9 (+/−16.15) to 343.9 (+/−15.9) P =.003. The difference between these groups, however, did not reach significance (P =.86). The pLAT group demonstrated a higher responder rate of (71%) versus the sLAT group (64%) based on the CCS although not reaching significance (P =.56). Conclusions: Use of both the pLAT and sLAT method of programming demonstrated significant improvement in 6MHW distance at 3 months with pLAT demonstrating a slightly higher responder rate based on CCS (P =.56). pLAT should be considered at minimum as equivalent in patients with no intrinsic conduction. [ABSTRACT FROM AUTHOR]

We present measurements of thermally generated transverse spin currents in the topological insulator Bi2Se3, thereby completing measurements of interconversions among the full triad of thermal gradients, charge currents, and spin currents. We accomplish this by comparing the spin Nernst magneto-thermopower to the spin Hall magnetoresistance for bilayers of Bi2Se3/CoFeB. We find that Bi2Se3 does generate substantial thermally driven spin currents. A lower bound for the ratio of spin current density to thermal gradient is ..., and a lower bound for the magnitude of the spin Nernst ratio is -0.61 ± 0.11. The spin Nernst ratio for Bi2Se3 is the largest among all materials measured to date, two to three times larger compared to previous measurements for the heavy metals Pt andW. Strong thermally generated spin currents in Bi2Se3 can be understood via Mott relations to be due to an overall large spin Hall conductivity and its dependence on electron energy. [ABSTRACT FROM AUTHOR]

Objective: Class III obesity (body mass index [BMI] ≥ 40 kg m−2) significantly impairs the immune response to SARS‐CoV‐2 vaccination. However, the effect of an elevated BMI (≥ 25 kg m−2) on humoral immunity to SARS‐CoV‐2 infection and COVID‐19 vaccination remains unclear. Methods: We collected blood samples from people who recovered from SARS‐CoV‐2 infection approximately 3 and 13 months of post‐infection (noting that these individuals were not exposed to SARS‐CoV‐2 or vaccinated in the interim). We also collected blood samples from people approximately 5 months of post‐second dose COVID‐19 vaccination (the majority of whom did not have a prior SARS‐CoV‐2 infection). We measured their humoral responses to SARS‐CoV‐2, grouping individuals based on a BMI greater or less than 25 kg m−2. Results: Here, we show that an increased BMI (≥ 25 kg m−2), when accounting for age and sex differences, is associated with reduced antibody responses after SARS‐CoV‐2 infection. At 3 months of post‐infection, an elevated BMI was associated with reduced antibody titres. At 13 months of post‐infection, an elevated BMI was associated with reduced antibody avidity and a reduced percentage of spike‐positive B cells. In contrast, no significant association was noted between a BMI ≥ 25 kg m−2 and humoral immunity to SARS‐CoV‐2 at 5 months of post‐secondary vaccination. Conclusions: Taken together, these data showed that elevated BMI is associated with an impaired humoral immune response to SARS‐CoV‐2 infection. The impairment of infection‐induced immunity in individuals with a BMI ≥ 25 kg m−2 suggests an added impetus for vaccination rather than relying on infection‐induced immunity. [ABSTRACT FROM AUTHOR]

Workbench-size particle accelerators, enabled by Nb3Sn-based superconducting radio-frequency (SRF) cavities, hold the potential of driving scientific discovery by offering a widely accessible and affordable source of high-energy electrons and x-rays. Thin-film Nb3Sn RF superconductors with high quality factors, high operation temperatures, and high-field potentials are critical for these devices. However, surface roughness, non-stoichiometry, and impurities in Nb3Sn deposited by conventional Sn-vapor diffusion prevent them from reaching their theoretical capabilities. Here we demonstrate a seed-free electrochemical synthesis that pushes the limit of chemical and physical properties in Nb3Sn. Utilization of electrochemical Sn pre-deposits reduces the roughness of converted Nb3Sn by five times compared to typical vapor-diffused Nb3Sn. Quantitative mappings using chemical and atomic probes confirm improved stoichiometry and minimized impurity concentrations in electrochemically synthesized Nb3Sn. We have successfully applied this Nb3Sn to the large-scale 1.3 GHz SRF cavity and demonstrated ultra-low BCS surface resistances at multiple operation temperatures, notably lower than vapor-diffused cavities. Our smooth, homogeneous, high-purity Nb3Sn provides the route toward high efficiency and high fields for SRF applications under helium-free cryogenic operations. [ABSTRACT FROM AUTHOR]

Strong damping‐like spin‐orbit torque (τDL) has great potential for enabling ultrafast energy‐efficient magnetic memories, oscillators, and logic. So far, the reported τDL exerted on a thin‐film magnet must result from an externally generated spin current or from an internal non‐equilibrium spin polarization in non‐centrosymmetric GaMnAs single crystals. Here, for the first time a very strong, unexpected τDL is demonstrated from current flow within ferromagnetic single layers of chemically disordered, face‐centered‐cubic CoPt. It is established here that the novel τDL is a bulk effect, with the strength per unit current density increasing monotonically with the CoPt thickness, and is insensitive to the presence or absence of spin sinks at the CoPt surfaces. This τDL most likely arises from a net transverse spin polarization associated with a strong spin Hall effect, while there is no detectable long‐range asymmetry in the material. These results broaden the scope of spin‐orbitronics and provide a novel avenue for developing single‐layer‐based spin‐torque memory, oscillator, and logic technologies. [ABSTRACT FROM AUTHOR]

Background We sought to develop a proteomics-based risk model for lung cancer and evaluate its risk-discriminatory performance in comparison with a smoking-based risk model (PLCOm2012) and a commercially available autoantibody biomarker test. Methods We designed a case-control study nested in 6 prospective cohorts, including 624 lung cancer participants who donated blood samples at most 3 years prior to lung cancer diagnosis and 624 smoking-matched cancer free participants who were assayed for 302 proteins. We used 470 case-control pairs from 4 cohorts to select proteins and train a protein-based risk model. We subsequently used 154 case-control pairs from 2 cohorts to compare the risk-discriminatory performance of the protein-based model with that of the Early Cancer Detection Test (EarlyCDT)-Lung and the PLCOm2012 model using receiver operating characteristics analysis and by estimating models' sensitivity. All tests were 2-sided. Results The area under the curve for the protein-based risk model in the validation sample was 0.75 (95% confidence interval [CI] = 0.70 to 0.81) compared with 0.64 (95% CI = 0.57 to 0.70) for the PLCOm2012 model (P difference =.001). The EarlyCDT-Lung had a sensitivity of 14% (95% CI = 8.2% to 19%) and a specificity of 86% (95% CI = 81% to 92%) for incident lung cancer. At the same specificity of 86%, the sensitivity for the protein-based risk model was estimated at 49% (95% CI = 41% to 57%) and 30% (95% CI = 23% to 37%) for the PLCOm2012 model. Conclusion Circulating proteins showed promise in predicting incident lung cancer and outperformed a standard risk prediction model and the commercialized EarlyCDT-Lung. [ABSTRACT FROM AUTHOR]

Phenomenon: Many academic medical centers (AMCs) have a history of separating patients on the basis of insurance status. In New York State, where Black and Latino patients are more than twice as likely to have Medicaid as white patients, this practice leads to de facto racial segregation in healthcare. Emerging evidence suggests that this segregation of care is detrimental to both patient care and medical education. Medical students are uniquely positioned to be change makers in this space but face significant barriers to speaking out about these disparities and successfully advocating for institutional change. Approach: The authors designed, piloted, and distributed a 16-item survey on segregated care to third-year medical students at a large academic medical center in New York City. Students were asked both open- and close-ended questions about witnessing separation and differences in patient care on the basis of insurance during their clinical rotations. The survey was shared with 140 students in March 2019 with a response rate of 46.4% (n = 65). Preliminary findings were presented to school and hospital administrators. Findings: More than half of survey respondents reported witnessing separation of patient care or differences in patient care on the basis of insurance (56.3%, n = 36 and 51.6%, n = 33 respectively). Many students reported that these experiences contributed to cynicism and burnout. The authors leveraged these results to advocate for quality improvement measures. In Ob-Gyn, department leadership launched a clinical transformation taskforce and recruited a new Vice Chair of Clinical Transformation/Chief Patient Experience Officer, whose role includes addressing segregated care and disparities in health outcomes. The hospital committed to establishing integrated practices in new clinical spaces and launching a similar survey among house staff. Insights: Many medical students experience and participate in segregated care during their clerkships and this has the potential to impact their education. Medical students are well-positioned to recognize segregated care across health systems and leverage their experiences for advocacy. A survey-based approach can be a powerful tool enabling students to collect these experiences to address segregated care and other health equity issues. [ABSTRACT FROM AUTHOR]

Background: Symptomatic mitral regurgitation (MR) is associated with high morbidity and mortality that can be ameliorated by surgical valve repair or replacement. Despite this, many patients with MR do not undergo surgery. Transcatheter mitral valve replacement (TMVR) may be an option for selected patients with severe MR.Objectives: This study aimed to examine the effectiveness and safety of TMVR in a cohort of patients with native valve MR who were at high risk for cardiac surgery.Methods: Patients underwent transcatheter, transapical delivery of a self-expanding mitral valve prosthesis and were examined in a prospective registry for short-term and 30-day outcomes.Results: Thirty patients (age 75.6 ± 9.2 years; 25 men) with grade 3 or 4 MR underwent TMVR. The MR etiology was secondary (n = 23), primary (n = 3), or mixed pathology (n = 4). The Society of Thoracic Surgeons Predicted Risk of Mortality was 7.3 ± 5.7%. Successful device implantation was achieved in 28 patients (93.3%). There were no acute deaths, strokes, or myocardial infarctions. One patient died 13 days after TMVR from hospital-acquired pneumonia. Prosthetic leaflet thrombosis was detected in 1 patient at follow-up and resolved after increased oral anticoagulation with warfarin. At 30 days, transthoracic echocardiography showed mild (1+) central MR in 1 patient, and no residual MR in the remaining 26 patients with valves in situ. The left ventricular end-diastolic volume index decreased (90.1 ± 28.2 ml/m2 at baseline vs. 72.1 ± 19.3 ml/m2 at follow-up; p = 0.0012), as did the left ventricular end-systolic volume index (48.4 ± 19.7 ml/m2 vs. 43.1 ± 16.2 ml/m2; p = 0.18). Seventy-five percent of the patients reported mild or no symptoms at follow-up (New York Heart Association functional class I or II). Successful device implantation free of cardiovascular mortality, stroke, and device malfunction at 30 days was 86.6%.Conclusions: TMVR is an effective and safe therapy for selected patients with symptomatic native MR. Further evaluation of TMVR using prostheses specifically designed for the mitral valve is warranted. This intervention may help address an unmet need in patients at high risk for surgery. (Early Feasibility Study of the Tendyne Mitral Valve System [Global Feasibility Study]; NCT02321514). [ABSTRACT FROM AUTHOR]

Experimental and epidemiological data suggest that vitamin D play a role in pathogenesis and progression of cancer, but prospective data on head and neck cancer (HNC) and oesophagus cancer are limited. The European Prospective Investigation into Cancer and Nutrition (EPIC) study recruited 385,747 participants with blood samples between 1992 and 2000. This analysis includes 497 case-control pairs of the head and neck and oesophagus, as well as 443 additional controls. Circulating 25(OH)D3 were measured in pre-diagnostic samples and evaluated in relation to HNC and oesophagus cancer risk and post-diagnosis all-cause mortality. After controlling for risk factors, a doubling of 25(OH)D3 was associated with 30% lower odds of HNC (OR 0.70, 95% confidence interval [95% CI] 0.56-0.88, Ptrend = 0.001). Subsequent analyses by anatomical sub-site indicated clear inverse associations with risk of larynx and hypopharynx cancer combined (OR 0.55, 95CI% 0.39-0.78) and oral cavity cancer (OR 0.60, 95CI% 0.42-0.87). Low 25(OH)D3 concentrations were also associated with higher risk of death from any cause among HNC cases. No clear association was seen with risk or survival for oesophageal cancer. Study participants with elevated circulating concentrations of 25(OH)D3 had decreased risk of HNC, as well as improved survival following diagnosis. [ABSTRACT FROM AUTHOR]

The article presents the author's experience of handling a patient in the respiratory isolation room, who was presented with end-stage AIDS, fever and altered mental status. It states that his cachexia, Kaposi's sarcoma, and known intravenous drug use showed that he was teeming with HIV and hepatitis. It mentions that the masogastric (NG) tube is the most uncomfortable procedures for conscious patients.

The author reflects on the trend towards sending U.S. medical students overseas for global health experiences that involve medical mission work. According to the author, there are several poor, marginalized and underserved people in the country that needs medical attention. He describes the case of a Haitian family living on the Upper West Side of Manhattan who faces several health problems but are not eligible for any medical care. He points out that passion is an important element in defining the concepts of altruism and service for medical students.

The article looks at possible ways to measure and control orbital angular momentum on the atomic scale with electron microscopes. A study conducted by Masaya Uchida and Akira Tonomura demonstrated the use of orbital angular momentum in an electron microscope. Meanwhile, Jo Verbeeck and He Tian of the University of Antwerp, and Peter Schattschneider of the Vienna University of Tecnhnology produced a hologram by digitally interfering a vortex beam with a reference plane wave in a computer.

Looks into the process as to how doping high-temperature semiconductors with calcium improves their current-carrying capacity. Efforts of research facilities to develop wires from high-temperature semiconductors; Details of the processes of the doping mechanism; Contention of the author that the expansion of the dislocation cores is astonishing due to its nature to depress superconductivity and block the flow of the supercurrent; Highlights of the research.

The article informs that nanotechnology is the manipulation of matter at the nanometer scale and promises to make great changes in culture. The importance of nanotechnology has been recognized by the federal government, which has funded the National Nanotechnology Initiative since 2001. Nanotechnology includes science and engineering concepts and tools, and chemists, with their long experience at manipulating matter, are ideally suited to play key roles in its development. While there are many graduate programs and professional journals devoted to nanotechnology research, there are few examples of nanotechnology in undergraduate education.

Over the past decade, transcatheter mitral valve replacement (TMVR) technologies have evolved with the objective of improving outcomes for patients with severe mitral regurgitation (MR) deemed unsuitable for conventional mitral valve surgery. Although the safety and efficacy of transcatheter edge‐to‐edge mitral valve repair (TEER) is well‐established, there is a sense amongst innovators that a major advantage of TMVR may be to offer a more complete solution for the correction of MR in patients whose complex anatomy means that the likelihood of achieving grade 0 or 1 MR with TEER is low. However, abrupt correction of MR in a poorly prepared left ventricle poses a number of unique haemodynamic challenges, particularly when sudden elimination of regurgitant flow causes a relative increase in left ventricular (LV) afterload. Rapid reduction in LV cavity size following MR elimination may itself result in relative LV outflow tract obstruction (LVOTO), irrespective of the intrinsic risk of LVOTO associated with TMVR. Nevertheless, TMVR on a beating heart affords the opportunity to study real‐time invasive cardiac indices in high‐risk patients with acute reversal of severe MR. [ABSTRACT FROM AUTHOR]

Biological systems convert chemical energy into mechanical work by using protein catalysts that assume kinetically controlled conformational states. Synthetic chemomechanical systems using chemical catalysis have been reported, but they are slow, require high temperatures to operate, or indirectly perform work by harnessing reaction products in liquids (e.g., heat or protons). Here, we introduce a bioinspired chemical strategy for gas-phase chemomechanical transduction that sequences the elementary steps of catalytic reactions on ultrathin (<10 nm) platinum sheets to generate surface stresses that directly drive microactuation (bending radii of 700 nm) at ambient conditions (T = 20 °C; Ptotal = 1 atm). When fueled by hydrogen gas and either oxygen or ozone gas, we show how kinetically controlled surface states of the catalyst can be exploited to achieve fast actuation (600 ms/cycle) at 20 °C. We also show that the approach can integrate photochemically controlled reactions and can be used to drive the reconfiguration of microhinges and complex origami- and kirigami-based microstructures. [ABSTRACT FROM AUTHOR]

Magnetic skyrmions hold promise for spintronic devices. To explore the dynamical properties of skyrmions in devices, a nanoscale method to image spin textures in response to a stimulus is essential. Here, we apply a technique for operando electrical current pulsing of chiral magnetic devices in a Lorentz transmission electron microscope. In ferromagnetic multilayers with interfacial Dzyaloshinskii–Moriya interaction, we study the creation and annihilation of skyrmions localized by point-like pinning sites due to defects. Using a combination of experimental and micromagnetic techniques, we establish a thermal contribution for the creation and annihilation of skyrmions in our study. Our work reveals a mechanism for controlling skyrmion density, which enables an examination of skyrmion magnetic field stability as a function of density. We find that high-density skyrmion states are more stable than low-density states or isolated skyrmions resisting annihilation over a magnetic field range that increases monotonically with density. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the safety and efficacy of corneal collagen crosslinking (CXL) for the treatment of corneal ectasia after laser refractive surgery. Design Prospective, randomized, multicenter, controlled clinical trial. Participants One hundred seventy-nine subjects with corneal ectasia after previous refractive surgery. Methods The treatment group underwent standard CXL, and the sham control group received riboflavin alone without removal of the epithelium. Main Outcome Measures The primary efficacy criterion was the change over 1 year of topography-derived maximum keratometry (K), comparing treatment with control groups. Secondary outcomes evaluated were corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent, endothelial cell count, and adverse events. Results In the crosslinking treatment group, the maximum K value decreased by 0.7 diopters (D) from baseline to 1 year, whereas there was continued progression in the control group (1.3 D difference between treatment and control, P < 0.0001). In the treatment group, the maximum K value decreased by 2.0 D or more in 14 eyes (18%) and increased by 2.0 D or more in 3 eyes (4%). The CDVA improved by an average of 5.0 logarithm of the minimum angle of resolution (logMAR) letters. Twenty-three eyes (32%) gained and 3 eyes (4%) lost 10 or more logMAR letters. The UDVA improved 4.5 logMAR letters. Corneal haze was the most frequently reported crosslinking-related adverse finding. Conclusions Corneal collagen crosslinking was effective in improving the maximum K value, CDVA, and UDVA in eyes with corneal ectasia 1 year after treatment, with an excellent safety profile. CXL is the first approved procedure to diminish progression of this ectatic corneal process. [ABSTRACT FROM AUTHOR]